Rotary or centrifugal pump operating with auxiliary turbines.



No. 879,059. PATENTED FEB. 11, 1908.

H. LUDEWIG. v ROTARY 'OR GENTRIPUGAL PUMP OPERATING WITH AUXILIARYTURBINES.

APPLICATION FILED APR. 24. 1905.

2 SHEETS-SHEET 1.

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No. 879,059. PATENTBD FEB.11, 1908.

H. LUDEWIG.. ROTARY OR CENTRIFUGAL PUMP OPERATING WITH AUXILIARYTURBINES.

APPLICATION FILED APR. 24. 19055.

2 SHEETS-SHEET 2.

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Java/2502 lzkrz cfizm To all whom it may concern:

. pump wheel into the cells of the 'duit pipes should not excee 20HEINRICH LUDEWIG, OF CHARLOTTENBURG, GERMANY.

:ROTARY OR CENTBIIUGAL PUMP OPERATING WITH AUXILIARY TURBINES.

Jim-879,069.

Specification of Letters ratent.

Patented Feb. 11, 1908.

Application filedllpril 24. 1905- Serial No- 267.253-

Be it-known that I, HEINRICH Lunnwro, a? subject of the German Emperor,residing at 'No. 7 Spandauerstrasse, Charlottenburg, near Berlin, in theGerman Empire, professor of "the Koniglichen-Technischen Hochschule ini'Berlin, have invented certain new and use- $111 Improvements in "Rotaryor Centrifugal. Pumps'O erating with Auxiliary Turbines, of which t efollowing is aspecification.

In centrifugal pumps in which the pump; disk leads directly into the endof the casi -eonnected to the rising main the absolute; velocity ofdelivery of the pressure fluid is 'mostly lost by concussion andformation of: eddiesywith heights of'lift that are not very *small thevelocity is considerable at the com-' mencement, while the velocit oneor two. "meters Ipler second, even with considerable lifts. is loss of seed can, under certain circumstances, be're need by means of-fixed guideblades arranged around the pumpwheel in the known manner. This,however,

necessitates the condition that the j ump ivs'rheel-shall only be drivenat a certain avorg able number of revolutions, i. 6. with a cer-' tainperipheral velocity, in order that the ressure against the fixed guideblades'may e-avoided. By means of the guide blades "the-speed of thedischarge water from they ide ring is to be converted into pressure 0the water; -in consequence offthe'gradual alteration of: the sectionalarea of the cells, as the pressure of-the water in the cells of theguide ring, in; "creases in proportion to :the decrease of speed. Thisassumption, however, as shown. by ex eriments is only correct to a very,

liniite degree, for, evenwith the most care ful-determination of thesections ofthe cells, "there enerall occurs almost as greataloss as wita sud on change of section (see O'i'vt'Z' Ingem'eur 1878, page 98,-Schweizerische Banze'itung Vol. 42, No. 8, Fliegener .E'in- 'neuer Wegzm' Berecimwng der Stankur've Zettschmlft fit'r dos gesamteTurb'inenwesen 1906 pages J2 to 14). According to the present inventionsuch losses of energy are entirely avoided by arranging. beyond theguide ring of the pump an auxiliary turbine which acts at motor andconverts the kinetic 2 energy of the fluid into energy of rotation,

which is transmitted-back to the pump shaftin the con-.

into the rising so that the-external driving'power for'th'e 'pump forraising the liquid to a certain height is correspondingly reduced In theaccompanying drawings are shown *various modes of construction forcarrying out the said mventlon.

' Figure 1 shows a longitudinal section of the comblned' ump guideringand turbine ,"Figs.

2-and 3 s ow diagrammatic cross sections 5 thereof; Fig. 4 shows asimilar construction k adapted to a compound pump; Figs. 5 and'lfi ngishow a longitudinal section and part cross section of a modification inwhich the guide passages are'formed with a double curvature $10 that theturbine I acts with an outward ow. Fig. 1' shows a vertical section ofan arrangement in which a pum disk P is combined with a turbine dls'kranged between'thetwo disks .P and Ta there being arfixed ring of guideblades L. In this case P and T are connected together by one and thesame boss so as to form a single rotatin body; the pum disk and theturbine dis can, however, e constructed 'as separate bodies. "By-means0f the uide rin L interposed between the pump isk Ran the turine disk Tand abutting directly a ainst these,the'pressure fluid issuing from Iwith 'the'velocit C (Fi 2) is led as impact fluid to the 'tur ine anissues at the end of the guide'ring (Fig. 3) with the absolute velocityc 'into the turbine wheel, in order, there, to perform work. After theimpact fluid of the auxiliary turbine has imparted to this the greaterpart of its energy it will in leaving the turbine-with the speed 0';pass directly struction of t e auxiliary'turbine must there+ fore besuch that it acts only as turbinemotor and'not also as pump, increasingthe pressure.

If the liquid pressures, in front of and'behind the turbine wheel are toremain e ual the auxiliary turbine must act as a so-ca led equalpressure turbine, which has onl "to convert the kinetic ener of thefluidinto energy of rotation as abso ute im act head. Also, withintheguide-channels o the-guide 'ring any alteration in the pressure of theliquid passing through has to be avoided.

The interposed guide ring'is therefore to be constructed (incontradistinction to the construction of the; ordinary guide ringsapplied .beyond thepump disk) with enlargement'of mainof'the pump. Theconthe section of the guide passages in such manner that c =c Leavingout of consideration any unavoidable guide or friction resistance, thepressure at the outlet of the pump disk at the radius 1",, will be thesame as in front of the turbine .wheel at the radius 1" e and beyond theturbine wheel at the radius 1%. Consequently the pump has to becalculated in the same way as with theold construction of )ump withoutrear guide ring as though the kinetic energy of the fluid were almostentirely lost by impact against the pump casing. This a parent loss isreturned by means of the auxiliary turbine the more so the higher is theell iciency of the auxiliary turbine. To effect this the inlet radius7",, of the auxiliary turbine is chosensmaller than the outlet radius1",, of the pump wheel. The advantage of this is shown from thefollowing. The-impact speed 0, corresponds, with a smooth motion of theturbine, to a certain peripheral velocity W of the turbine wheel.

Consequently 1/ is dependent upon the peripheral velocity '12,, alreadydetermined, of the pump. The wheels P and T being arranged on one andthe same shaft have the same speed, so that o /v,,=r /r According to theknown rules of turbine construction it is of advantage, for obtaining agood useful effect, if the peripheral s eed o is I smaller than c viz.only about ha I? as great,

but as c is made equal to 0,, consequentl 4/ is smaller than 0,. Withthe pump wheel: according to the choice of the angle of the blades andthe speed of the pump, the absolute speed of issue c of the pressurewater is dependent upon the-chosen peripheral speed v of the pump wheel.

In order to keep the friction losses for water small in the guide ringwith a great c it is of advantage to make 0,, smaller than 0,, which maybe attained by a suitable choice of the angle of the 'pump blades.

With o smaller than 0,, and 0,, smaller than 1),, it follows that'o issmaller than.

1),. But the conditionthat 'v is to be smaller than a, is attained bymaking 1",, smaller than 1",. This condition which .determines thedimensions'of the inlet and outlet radii of the intermediate guide ringis therefore an essential feature of the invention. Consequently in theconstruction shown at Figs. 1, 4, 5 and 6 the inlet radius r',, is madesmaller than the outlet radius 1",, of the pump disk. As shown'in Fig. 1the guide ring and the turbine ring of the auxiliary turbine can be soarranged that the issuing water is led off in axial direction directlyinto the rising main. This arrangement is also facilitated by the factthat r,, must be chosen smaller than T, and consequently the outletradius ,r, of the turbine wheel can also be made so small that'theoutlet is situated directly around the shaft. With such axial dischargeof the liquid from the turbine the ini roved ump construction isrendered suitab e for t e combined construction of severalpumps in theform of a compound pump, as shown in vertical section in Fig. 4, as inthis case the liquid issuin axiall from the auxiliary turbine can be leddirect y to the inlet of the next pump disk.

If the auxiliary turbine is constructed for equal pressures of'the inletand outlet liquid,

it can be constructed according to the usual forms of equalpressureturbines, either as axial or as radlal turbine- If an outward- .flowradial turbine be chosen then, as shown in Figs. 5 and 6, the waterissuing from the turbine is led through an annular collecting channel tothe. rising main of the pump,

which is in that case arranged at the side of.

such channel. For enabhn such an arrangement to be used, the uide ring Lmust be formed with a' doub e curvature, as

shown.

The'intended advantage ofthe new construction over pumps of knownconstruction with guide ring can only'be attained if the auxiliaryturbine acts with good useful effect. It is, however, known that theequal pressure turbines are inferior as regards the useful effectsobtained in comparison with turbines operating with fall of ressure(reaction or excess pressure turbines) as is shown by the presentgeneral adaptationof the Francis turbine as excess pressure tur bine,that is, with fall of pressure, which, as is known, is effected by aproper choice of the .angles of the blades, and in particular of thecross sections of the passages of the turbine wheel. In this particularcase the water pressure at the line of the turbine radius 1", isarranged to be greaterthan that at the discharge radius 1",. Inconsequence of the condition c 0' the water pressure at the line ofradius r, is as great as at the line of radius r Consequently in thiscase the pump must be calcu ated as though it were mtended for a eaterlift, and therefore the velocity 0,, an the kinetic ener y of the fluidmust also be greater, but t e greater amount of rotary work re uisitefor this purpose isre ained in the tur ine with particuarly o0 usefuleffect, so that the total useful e ect of the pump having the reactionturbine is increased as compared witha pump with equal pressure turbine.To this improvement in the useful effect has to be added the fact thatthe excess pressure turbine can be-constructed in the same way as theusual form of Francis turbine of American coninto practical effect, Iclaim:

1. In an apparatus of the class set forth, a

centrifugal pump, with an auxiliary turbine of the turbine, the radiusof t e outlet of the pump and inlet of said guide ring being greaterthan the radius of the outlet of-the guide rin and inlet of the turbine,substantially as escribed.

2. In an apparatus of the class set forth, a

I centrifugal pump, with an auxiliary turbine o eratin as motor mountedon the same s aft an revolving at the same speedas the I pump, and afixed guide ring interposed between the outlet 0 the pum and the inletof the turbine, the radius of t e outlet of the pump and inlet of saidguide ring being greater than the radius of the outlet of the guide ringand inlet of the turbine, and the j outlet of the turbine being arrangedto immediately surround the pump shaft so that the liquid issuestherefrom in the axial direction substantially as and for the purposedescribed. A v 1 p -3. In an apparatus of'the class set forth, acentrifugal pump, an auxiliary turbine operating as motor with drop ofpressure (reaction turbine) mounted ontthe same shaft and revolving atthe same speed as the pump, and a fixed guide ring interposed betweenthe outlet of the pump and the inlet of the turbine, the radius of theoutlet of the. pump and inlet of said guide ring being greater than theradius of the outlet of the guide rin and inlet of the turbine,substantially as escribed.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

HEINRICH LUDEWIG.

Witnesses WoLnEMAR HAUPT, HENRY HASPER.

